[Simh] A lost 18b peripheral

[Bob Supnik]

Looking through the XVM/MUMPS15 listing, I saw that the timesharing 
terminals were attached via a DC01 communications multiplexer. There's 
no reference to such a device anywhere in the 18b literature on Bitsavers.

Because the PDP15 is a contemporary of the PDP8/I and the KI10, I 
thought it might be a variant of their multiplexers, but I can't find a 
match.

Another mystery.

/Bob